STRUCTURE OF COMPOSITES BASED ON MULTI-WALL CARBON NANOTUBES AND TIN OXIDE
DOI:
https://doi.org/10.17308/kcmf.2018.20/515Keywords:
multi-walled carbon nanotubes, composite, tin oxide, chemical vapor deposition, magnetron sputtering, X-ray spectroscopy.Abstract
The main purpose of this work was to study the structure, morphology, and composition of composites based on multi-walled carbon nanotubes (MWCNTs) and tin oxide obtained by the methods of chemical vapour deposition and magnetron sputtering. X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XANES), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) were used to analyse the structure and composition of the obtained composites. It is shown that the morphology and structure of the formed composites depend substantially on the change in the structure and chemical state of the outer walls of MWCNTs during the process of depositing tin oxide on their surface.
It is established that when using the method of chemical vapour deposition, no significant changes in the crystal structure and chemical state of carbon in the walls of the MWCNTs are observed. The MWCNTs surface weakly oxidises with the formation of carboxyl and carbonyl groups (C = O, COOH). As a result, tin oxide is distributed along the surface of the MWCNTs as separate clusters that interact weakly with the outer walls of carbon nanotubes. It is shown that tin oxide in clusters is mainly represented by defective crystalline SnO2.
The magnetron sputtering method contributes to the formation of a large number of structural defects and a considerable oxidation of the MWCNTs surface with the formation of functional oxygen-containing groups of different composition (C-OH, C = O, COOH, C-O-C, -CO3, etc.). Significant functionalization of the walls of carbon nanotubes leads to the chemical interaction between tin oxide and the surface of MWCNTs. This results in an increase in interracial adhesion in the composite, whereby the tin oxide uniformly covers the walls of the MWCNTs as a continuous layer.
The obtained results can be used in the development of composites based on carbon nanotubes and metal oxides with the required structure and a set of physicochemical characteristics.
ACKNOWLEDGEMENTS
The authors would like to thank Yu.A. Stenkin, PhD in Chemistry, and V.Ye. Roslikov for synthesising original MWCNTs and composites by magnetron sputtering and D.A. Smirnova and the administration of Russian and German source of synchrotron radiation BESSY II (Berlin, Germany) for their help in conducting measurements by the XPS and XANES methods. The authors would like to thank Omsk Regional Centre for Collective Use of the Siberian Branch of the Russian Academy of Sciences for the equipment to study samples by SEM and EDX methods.
The work was performed under the state task of Omsk Regional Centre for Collective Use of the Siberian Branch of the Russian Academy of Sciences in accordance with the Programme of Fundamental Research of the Russian Academies of Sciences for 2013-2020 in area II.9, project II.9.2.1 (state registration number in the integrated national information system of research, development, and engineering projects – ААА-А17-117041210227-8), and also was partial supported by a grant from the Russian Foundation for Basic Research no. 18-32-00233 mol_a, regarding the analysis of composites by the SEM method.
